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Query: UMLS:C0001511 (Adhesion)
 5,955 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Heparin inhibited monolayer adhesion of washed human and rabbit platelets to collagen-coated glass at 2.5 and 20 units/ml concentration, in the absence of red cells. Adhesion of rabbit platelets to de-endothelialized rabbit aorta, under similar conditions, was less strongly inhibited but no inhibition was seen at 40% haematocrit. Addition of plasma reduced, rather than enhanced heparin activity and hirudin 0.5 units/ml had no significant effect. Heparin also inhibited platelet aggregation, release of (14C) 5-HT and production of malondialdehyde in response to collagen and thrombin. Inhibition of thrombin-induced activity was greater in the presence of plasma. However, heparin enhanced aggregation and release evoked by ADP and did not consistently inhibit MDA synthesis produced by arachidonate. The results indicate that in addition to the effects of heparin on platelet function mediated by anti-thrombin activity and the previously described augmentation of responses to ADP, heparin has weak inhibitory activity against platelet-collagen interactions. Binding of heparin to the platelet membrane (and to surfaces to which platelets adhere) could account for these findings by causing non-specific interference with agonist-receptor interactions.
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PMID:Effect of heparin on platelet monolayer adhesion, aggregation and production of malondialdehyde. 710 Dec 45

Human platelets adhere to trimeric Type 1 chick collagen that was covalently linked to plastic slides, providing the basis for a well-defined quantitative assay. The number of platelets that adhere is a function both of platelet concentration and of collagen density on the slides. In contrast with other in vitro assays using collagen that is not covalently linked to the substratum, we found no platelet-platelet aggregation. Adhesion was absolutely dependent on Mg2+, whereas Ca2+ was ineffective. Native trimeric collagen conformation was required for adhesion, since platelets did not bind to slides containing heat-denatured collagen, or isolated alpha 1(1) or or alpha 2(1) chains. Modifications of collagen oligosaccharides had no effect on adhesion. Adhesion was inhibited by cytochalasin D but was not affected by prostaglandin E1, apyrase, acetylsalicylic acid, or theophylline. Because this assay measures platelet-collagen adhesion in the absence of platelet-platelet aggregation, it should facilitate identification of the platelet surface components that directly mediate this adhesion.
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PMID:Adhesion of human platelets to immobilized trimeric collagen. 714 92

Adhesion of calf lens epithelial cells to lens capsule, their natural basement membrane was found to be considerably more rapid than either to plastic or to type I or type IV collagen coated surfaces. No polarity of the basement membrane was observed as the cells were able to attach to either side of the anterior or posterior lens capsule; a prerequisite for adhesion to the lenticular side of the anterior capsule was the prior removal of its epithelial cell layer. The attachment was energy-dependent and required calcium and magnesium ions, but was not enhanced by the presence of serum. Neither exogenous fibronectin nor laminin was able to stimulate attachment or spreading of lens cells to the capsule even when the cells had been treated with cycloheximide. Since rapid adhesion and spreading takes place in this lens cell-lens capsule system without requirement of exogenous macromolecules, it provides a favorable model for investigating the determinants in epithelial cell-basement membrane interactions.
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PMID:Lens epithelial cell adhesion to lens capsule: a model system for cell-basement membrane interaction. 717 30

Collagen is one of the major constituents of glomerular basal lamina. Its thrombogenecity has been systematically studied in our laboratory by aggregometry, adenine nucleotide release assay, and electron microscopy. The purified human glomerular basal lamina (HGBL) preparation does not induce platelet degranulation, nucleotide release, or aggregation, although adhesion and spreading of platelets on HGBL are observed. Isolated monomeric HGBL collagen or insoluble HGBL collagen in its native state of organization are similarly inactive. Modification of carbohydrate moieties by sialase, alpha-glucosidase, or sodium periodate oxidation has no effect on HGBL's inability to induce platelet release reaction or aggregation. Therefore, HGBL collagen is not thrombogenic as has been suspected. Adhesion and spreading of platelets on HGBL, which require the noncollagen constituents of HGBL and divalent cations, represent a temporary capillary pavement for endothelial defect distinct from thrombogenic activity of platelets.
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PMID:Human platelets and glomerular basal lamina interaction. 732 14

Multiple, linked interactions between the platelet surface and collagen fibers have been implicated in the initiation of platelet secretion and subsequent aggregation. The formation of such multiple simultaneous interactions could give rise to high affinity adhesion of platelets to collagen even though the affinity of the individual interactions may be much weaker. This concept has been tested by measuring the adhesion of platelets to collagen under conditions which could effect the formation of multiple interactions. Adhesion is markedly diminished at 4 degrees C but not at 23 or 37 degrees C. Metabolic inhibitors such as 2-deoxyglucose and Antimycin A do not inhibit adhesion although they virtually abolish subsequent aggregation. Brief formaldehyde fixation of platelets greatly reduces adhesion. These results are consistent with the concept that the formation of multiple linked interactions between the platelet surface and collagen are important in platelet-collagen adhesion and that mobility of platelet membrane components is required for the clustering of these interactions in focussed regions on the platelet surface.
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PMID:Platelet-collagen adhesion-membrane fluidity and the development of high affinity adhesion through multiple interacting sites. 734 33

Polyunsaturated fatty acids influence several steps involved in metastasis formation in animal tumor models. During the process of metastasis from the primary site, tumor cells adhere to the endothelium and underlying basement membrane before extravasation and secondary growth. The purpose of this study was to determine the effect of unsaturated fatty acids on adhesion of human breast cancer cell lines to components of the basement membrane. Cells were cultured in low-serum medium for five days with or without added unsaturated fatty acids. Adhesion assays were conducted by incubating cells with basement membrane substrates coated on 96-well plates, washing to remove nonadherent cells, and staining adherent cells with crystal violet. Linoleic acid (LA) and eicosapentaenoic acid increased adhesion of the metastatic cell line MDA-MB-231 to Matrigel and type IV collagen, while eicosapentaenoic acid decreased adhesion of the less metastatic cell line SK-BR-3 to these two basement membrane substrates. Oleic acid increased adhesion of MDA-MB-231 cells to Matrigel and fibronectin. Nordihydroguaiaretic acid and high concentrations of indomethacin, each of which inhibits the lipoxygenase pathway of arachidonate metabolism, were effective in reversing the stimulatory effect of LA on MDA-MB-231 cell adhesion. A protein kinase C inhibitor likewise suppressed the increase in adhesion observed when MDA-MB-231 cells were incubated in media with added LA. Unsaturated fatty acids modified the adhesive properties of human breast cancer cell lines in vitro, and LA appeared to increase human breast cancer cell adhesion to extracellular matrix components by activating lipoxygenase and/or protein kinase C pathways.
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PMID:Unsaturated fatty acid effects on human breast cancer cell adhesion. 749 Dec 98

We studied the interaction between Trypanosoma congolense and bovine aorta endothelial (BAE) cell monolayers. Our findings suggest that trypanosomes adhere predominantly to the flattened, peripheral cell surface domains as well as to filamentous endothelial outgrowths that are present during in vitro cultivation in non-confluent monolayers. Adhesion is mediated exclusively by the flagellum in a distinct geometrical order with respect to the flagellar cytoskeleton. Thus, it is possible to define exactly the trypanosomal cell surface domain involved in the attachment process. After 24-48 h of cultivation on monolayers, trypanosomes start to develop short, filopodia-like flagellar protrusions, which serve as additional elements in assisting parasite attachment. Small filaments (3-5 nm) also serve as cross-links between flagellar and endothelial cell surface membranes. Lectin-gold labeling shows that these cross-links contain sialic acid residues. In vitro assays confirm that sialic acid is involved in the adhesion process, whereas the extracellular matrix (ECM) proteins fibronectin, collagen, laminin and vitronectin are not. The presence of T. congolense exhibits a mitogenic effect on BAE cells.
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PMID:Flagellum-mediated adhesion of Trypanosoma congolense to bovine aorta endothelial cells. 750 41

Integrin expression and function is largely modulated by cell activation. Here we provide evidence that long term activation of human NK cells results in a marked modulation of beta 1-integrin expression and adhesive functions. By flow cytometry and immunochemical analysis we have detected induction of alpha 1 beta 1 and alpha 2 beta 1, increased expression of alpha 4 beta 1 and alpha 5 beta 1, and decline of alpha 6 beta 1 on CD3-CD56+ NK cells generated from 10-day coculture of nonadherent PBMC with irradiated RPMI 8866 EBV+ lymphoblastoid B cell line. Adhesion assays performed on extracellular matrix-coated plates showed that, unlike fresh NK cells, long term-activated NK cells bind to native collagen I via alpha 2 beta 1 and to heat-denatured collagen I in an RGD-dependent manner, although they lose the ability to bind to laminin. In regard to the adhesion to FN, no major quantitative changes are observed after long term NK cell activation. However, whereas alpha 4 beta 1 and alpha 5 beta 1 completely mediate the adhesion of fresh NK cells to fibronectin, binding of activated NK cells is only partially beta 1-dependent and seems to involve also non-beta 1-integrin(s) recognizing and RGD sequence. The modulation of beta 1-integrin expression and the acquisition of new adhesive properties on long term-activated NK cells may be relevant for their traffic and tissue localization during inflammation and immune response.
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PMID:Long term activation of natural killer cells results in modulation of beta 1-integrin expression and function. 750 24

Adhesion to proteins of the extracellular matrix exerts a profound influence upon cell function and behavior. Similar adhesive interactions mediate the spreading of cultured cells upon artificial substrata. Recently we observed that thyrotropin (TSH) and intercellular contact regulated thyroid cell-substrate adhesion to inhibit cell spreading, but not initial attachment. This is a mechanism which preserves thyroid follicular differentiation in culture. In the present study we have investigated the role of cytoplasmic components in mediating thyroid cell adhesion to collagen. The earliest change associated with cell spreading was the accumulation of vinculin and phosphotyrosine in developing focal adhesions, which was followed by stress fiber and microtubule assembly. Genistein, an inhibitor of tyrosine kinases, and cytochalasin B inhibited cell spreading and focal adhesion formation without affecting initial attachment to substrate. In contrast microtubule disorganization by colchicine did not alter any parameter of thyroid cell-substrate adhesion. These observations indicate that protein tyrosine phosphorylation and dynamic microfilament integrity are essential for attached thyroid cells to spread upon substrate. They are therefore potential intracellular loci at which TSH and intercellular contact may regulate cell adhesion to extracellular matrix and influence thyroid cell behavior.
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PMID:Thyroid cell spreading and focal adhesion formation depend upon protein tyrosine phosphorylation and actin microfilaments. 750 54

We studied the expression of integrin alpha and beta chains on alveolar epithelia in normal and fibrotic lung tissue by immunohistochemistry. Alveolar epithelia and their precursor cells in fetal lung tissue consistently expressed alpha 1, alpha 2, alpha v and beta 1 chains. Neoexpression of alpha 4, alpha 6 and beta 4 chains was detected on alveolar epithelia of fibrotic lung tissue. Adhesion blocking assays with isolated type II pneumocytes were performed to investigate the substrate specificity of the alpha chains. alpha 1, alpha 2 and alpha 3 demonstrated a specificity for collagen, alpha 4, alpha 5 and alpha 6 for fibronectin, alpha 3 and alpha 6 for laminin and finally alpha 5 and alpha v for vitronectin.
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PMID:[Pattern of expression of integrins in alveolar epithelia of fetal and adult lungs and interstitial lung diseases]. 751


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